When you're actually cruising in Alaskan waters, it will be too cool to swim in outdoor pools no matter what time of year you go. In fact, many ships replace the towels they normally have near the pool with woolen blankets for those who want to stand outside near a glacier, to watch the world go by.

If you are starting and/or ending in Vancouver or Seattle, you may get a day when you can swim before or after you're up in Alaska.